Automatic circuit breaker



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March 18, 1930 w, LEY 1,750,895

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AUTOMATIC CIRCUIT BREAKER Filed March 30, 1928 4 Sheets-Sheet 5 in! 45 .44 H

132092140" We/m l eylawrcn 5y March 18, 1930'. w. LEYHAUSEN AUTOMATIC CIRCUIT BREAKER Filed March 30. 1928 4 Sheets-Sheet 4 my. 14 m 72 Patented Mar. 18, 1930 PATENT OFFICE WILHELM LEYI-IAUSEN, F NUREMBERG, GERMANY AUTOMATIC CIRCUIT BREAKER Application filed March 30, 1928, Serial No. 266,089, and in Germany August 14, 1926.

In automatic circuit breakers of the form of electromagnetic switches of threaded plug type, the utilization of the blowing action of the magnet-coil is of greatest importance for extinguishing the arc. The cutting-out speed is also of importance. This cutting out speed is, however, of no value in-preventing arcing when the magnet-coil is too far from the contacts for a blowing action. Such objections reside especially in plug-switches in which the switch contacts andthe releasing mechanism are arranged on the same side of the magnet-coil. In order to prevent overlapping of the are over the releasing mech- 5 anism the latter is separated by a partition from the switch contacts and releasing mechanism situated between the coil and the contacts, but with this arrangement the coil is too far distant from the contacts to exert a 0 sufliciently strong blowing action. i

Excess current-switches have further become known in which the releasing mechanism is arranged on one side of the magnetcoil and a switch-contact on the other side 5 of the coil. The connection between the releasing mechanism and the switch-contacts must then be conducted through the magnetcoil and generally formed by the plunger armature of the magnet-coil. Owing to this arrangement the contacts can be placed closer to the magnet-coil but this does not entirely eliminate jumping of the spark to the armature and coil and consequently to the releas-- ing mechanism.

According to the invention these objections are avoided by disposing the releasing means for the switch elements on one side of the magnet-coil and the switch-contacts carried rating the switch contacts, notwithstanding the employment of an insulating partition of the character described.

The invention has further for its object to arrange the automatic switches in such a manner that the thermic releasing device, provided on the switches besides the electromagnetic releasing device, can be made to operate at different normal current-intensities.

Several embodiments of the invention are illustrated, by way of example, in the accompanying drawings in which 1- Figs. 1 to 5 show an excess current-switch with plane-partition between the magnetcoil and the switch contacts and with a push button releasing device.

Figs. 1 and 2 show each the switch in vertical section, Fig. 1 in the cut-in position and Fig. 2 in the cut-out position.

Fig. 3 is a horizontal section taken just above the partition.

Figs. 4 and 5 show a modified closure for the aperture in the partition in two different. positions.

In Figs. 6 to 9 an excess current-switch with magnet-coil enclosed in a capsule is illustrated. I

Figs. 6 and 7 show each the switch in a vertical section in the cut-in and cut-out positions respectively. 89

Fig. 8 is a top-plan-view of the same, the lid of the casing being removed.

Fig. 9 is a vertical section through the switch, one of the switch arms being shown in elevation in Figs. 10 to 12, an excess cur- 85 rent-switch is shown in section, comprising a modified releasing device and push-buttons for switching on and off.

Figs. 10 and 11 show the switch in the cut-in and cut-out positions respectively.

Fig. 12 shows the releasing device in elevation viewed in the direction of the switcharm.

In Figs. 13 to 16 arrangements for adjusting the apparatus for employing difierent current-intensities for operating the thermal releasing device are illustrated.

tion of the arrangement and Figs. 15 and 16 show a second form of construction of the same. X

Fig. 17 shows diagrammatlcally a variable thermal releasing device by way of example.

Referring to Figs. 1 to 3 a disk 3 is arranged in the lower part 1 of the casing 1, 2 which carries the magnet and blowing coil 4 with a plunger armature 5. 4 a horizontal partition 22' of insulating material is mounted which has at the centre an opening 23 and two apertures 24, 24 near the edge. On axles 7, 7 the two-armed contactarms 8, 9 are pivotally mounted. On the end of each lower arm 9 a roller 12 of insulating material is arranged, a disk-6 on the end of the plunger armature 5 being disposed between these two rollers 12, 12. The upper arms 8, 8 extend through the apertures 24, 24 of partition 22 and their contacts 10, 11 engage each other above the opening 23, when the switch is in the position ready for use. Around the axles 7, 7 springs 16 are wound which press the rollers 12 against disk 6. When excess current occurs, the plunger armature 5 is attracted by the magnet-coil 4.

so that the disk 6 releases the rollers 12 and the contacts 10 and 11 move outward or away from one another under the pressure of springs 16. The switch is then in the cut-out position shown in Fig. 2.

A push-button 18 serves for closing thecircuit. It is controlled by a spring 19. From the push-button extends the downwardly directed switch-rod 20 which fits in the opening 23. When the push-button 18 is depressed the switch-rod 20 pushes the armature 5 downwards into the cut-in position. The contacts 10, 11 are thereby returned to normal osition so that their contact portions ear against the switch-rod and come into engagement as soon as the push-button has returned into its initial position. If at this time,however, the circuit is 'still overloaded another cut-out action will take place instantaneously, as will be readily understood.

The descending movement of the plunger armature 5 is limited by an adjusting screw 14 screwed'through a bush 13 and by means of which the switch is adjusted to the desired intensity of releasing current. As soon as the plunger armature is attracted, an insulating piece 15 on the top-end of the same closes the opening 23 in the partition 22 so that the are formed between the contact portions of the contacts 10, 11 will be confined to the top part of the casing and prevented from reaching the coil. 4

gs. 4 and-5 show a modified construction of closure for the opening 23 of partition 22 in two difierent positions. A disk 17 is pressed by the pressure of a spring 21 from below into the opening 23 and .normally closes the same. When the push-button 18 is depressed the switch-rod 20 pushes the disk 17 against the plunger armature 5 and'depresses Above the coil.

this armature togetherv with the disk. When the push-button returns to its initial position, the opening 23 is instantaneously closed by the disk 17. I

The partition 22 separates-the arc space or chamber 25 from the coil and from the releasing device.

The excess current-switch shown in Figs. 6 to 9 differs from that shown in Figs. 1 to 3 in that the magnet-coil 4, in which an auxiliary, stationary armature 39 is mounted is enclosed by a capsule 26 and thatthe closing of the contacts 10, 11 is carried out by means of a stud 27 of a foot-contact. The capsule 26 is mounted on the disk 3. The two-armed contact-arms 8, 9, pivotally mounted on the axles 7, 7, are connected with one another by a toggle-lever 28, 29, the arms of which are oscillatably mounted on a common bolt 30. On this bolt 30 acts the plunger armature 5. The lever-arm 28 is made 0t insulating material.

When excess current occurs the plunger armature 5 is attracted and the toggle-lever is bent. The contacts 10 and 11 are moved suddenly, in opposite directions by the action of the springs 16, 16. The are is blown to the right or left side by the coil 4. The switch is then in the position shown in Fig. 7.

To return the switch into the cut-in position stud 27 must be pulled down. To this stud 27 a rod 31 is connected, the upper end of which has a longitudinal slot 32 engaging over the pivot-bolt 30. A spiral-spring 33 wound around rod 31, the lower end of said spring resting on a plate 34 and the upper end pressing against a pin 35 fixed in rod 31, serves to hold this rod in the raised position limited by a collar 36. On the pulling down of stud 27 the toggle-lever 28, 29 is stretched again.

At either side of the arms 8 a vertical partition 37 is mounted so that channels 38 are formed which completely enclose the arms.

In the excess current-switch shown in Figs. 10 to 12 the cutting-in and out is efi'ected by push-buttons arranged on one side (at the top) of the coil which operate through connecting rods the releasing device arranged on the opposite (bottom) side of the magnetcoil. The switch can thus be adjusted to the cutting-in position Without being unscrewed from its receiving socket.

The magnet-coil acting upon the plunger armature 5 is enclosed by a capsule 26. To the plunger armature 5 an elbow-lever 41 is hingedly connected by means of an axle 40, said elbow-lever being oscillat-ably mounted on a stationary stud 42 and controlled by dead centre-springs 50, attached at the one end to a transverse pin 43 of lever 41 and at the other end to stationary holding arms 44. On the stationary pivot-pin 42 a locking disk 45 is rotatably mounted which has a stationary contact 51.

notch 46 through which the pin 43 extends. The notch is, however, wider than the pin 43 is thick, so that a side wall of the notch will normally be spaced from the pin and will be brought to bear against said pin only after a certain part-rotation of the disk. The edge of disk 44 bears against a transverse pin 47 of a two-armed lever 49, pivotally mounted on a pivot-pin 48. WVhen the disk is in the position described, the lever 49 presses the movable spring contact 52 against the The switch is then in the switching-on position shown in Fig. 10.

When on excess current the plunger armature 5 is attracted by the magnet-coil, the e bow-lever 41 oscillates beyond the dead centre-position, the locking disk 45 remaining at rest. Then, when the lever 41 has completely moved beyond the dead centrepoint, the locking disk 45 is rotated so that it releases the lever 45, and the contact-spring 52 jumps back into the position shown in Fig. 11.

For cutting-in, the push-button 53 is depressed against the action of its spring 54. With this button 53 a separating element 55 is connected which stands transversely to the contacts 51 and 52. This separating element 55 when descending acts upon a shiftable rod 56 which has at the lower end a slot 57 indicated in dash-dot-lincs engaging over a bolt 60 of the elbow-lever 41. On the depression of the push-button 53 the elbow-lever 41 is therefore moved back beyond its dead centreposition and then returned by the action of the springs 50 into the position shown in Fig. 10. The locking disk 54 is rotated backward and pushes the lever 49 into the initial position and tries to press the contact-spring 52 against the stationary contact 51, this being however prevented by the lowered separating element 55.

When the push-button 53 is released, it is pushed upward together with the separating element 55 by the action of the spring 54 and the circuit is closed.

On the transverse stud 43 of the elbowlever 41 a push-rod 59 is pressed by the action of a spr1ng (not shown), said push-rod car- 'rying on the top-end a push-button 58. This push-button executes the same cutting-in and out "movements as the lever 41 and it is ob vious that, by depressing the push-button 58, the switch member 52 may at any time be shifted to cut out position.

An arrangement which permits regulation of the thermal-releasing device of the switch to act at different nominal current-intensities is shown in Fig. 17. The current flows through the wire 61 into'the coil 4 which encloses the plunger armature 5. From the coil 4 a wire 62 leads to abimetal strip 63 and thence, through a switch-arm 65 pivotally mounted at 64, to the wire 66. Above the bimetal strip 63 a transverse arm 67 is I switch non-responsive to short overloadings Within certain toleration time limits, but to efiect release of the switch when such overloads last a longer time. When for example the thermostat 63 has been regulated for 2 amp. it will have extended in one minute at 5 amp. to such a length that it lifts the plunger armature 5 and causes the releasing of the switch. W'hen-the overloading is of shorter duration, it is without effect.

Suppose the two shunts 68 and 69 be also tuned to 2 amp. WVhen then the switch-arm 64 is so adjusted that the bimetal strip 66 and the shunt 68 are parallel-connected, the nominal current-intensity amounts to 4 amp. and

it amounts to 6 amp., when the three elements 66, 68 and 69 are parallel-connected. By adjusting the switch-arm 65 the nominal current-intensity can be altered at will. It is evident that it is not necessary that for the parallel-connecting of the resistances to the bimetallic-strip a pivoted switch-arm be provided, as the connection of the resistances can be carried out in any other manner, and the resistances may be of any type.

In Figs. 13 and 14 the lower part of a plugswitch is illustrated, in which the alteration of the nominal current-intensity can be produced by altering the toot-contact-stud. The plug-body l carries the foot-contact-stud 70 which corresponds for example to a nominal current-intensity of 6 amp. It is connected by a metalstrip 71 and a Wire 72 to the thermostat (not shown) which is tuned to 6 amp. WVhen the nominal current-intensity has to be increased to 10 amp., a metal-sleeve 73 is pushed over the foot-contact 7 O. This metalsleeve is connected by contact-finger 74, spring 75 and wire 80 to a shunt resistance (not shown).

To adjust the switch to a nominal currentintensity of 15 amp., another sleeve 76 is pushed over the sleeve 73. The sleeve 76 is then connected by a finger 77, spring 78 and wire 79 to a shunt resistance which, together with the shunt resistance connected to sleeve 73, will be tuned to 15 amp.

Instead of the sleeves, interchangeable studs of solid cross-section may be used, the diameter or length of which corresponds to the nominal current-intensity. Figs. 15 and 16 show such an arrangement by way of example.

The metal piece-34,, mounted in the plugbody 1 is connected to a thermostat (not shown) by a wire 81. On the top-end of the stud 7 0 of the foot-contact a tube 82 made ofelectric nonconducting material is mounted,

which carries in its top-end a contact-screw 83. Between this contact-screw 83 and the stud 70 a resistance 84 is arranged. The screw 83 is screwed into a contact-piece 85, which is connected to the switch by a wire 86 so that the resistance 84 acts as shunt to the thermostat. When the stud 70 is turned to the left, the screw 83 is unscrewed from the contact-piece 85, and the stud can be removed like a cartridge and another of a different value substituted therefor. The length of the stud varies in accordance with the currentintensities. Fig. 16 shows a short stud 87 designed for lighter current-intensities.

I claim 1. An automatic circuit breaker of the screw-plug type comprising a casing having a spark space, a magnet coil having one of magnet-coil which faces the spark-space.

2. A circuit breaker as specified in claim 1, embodying an insulating partition be tween said magnet-coil and said spark-space having two apertures at diametrically oppo site points for passage of said connectingmeans.

3. A c1rcu1t breaker as speclfied ln-claim 1, embodying a push-button, a switch-rod on said push-button, an insulating partition between said magnet-coil and said spark-space having two apertures at opposite points near the edge thereof for passage of said connecting-means and a central opening for said switch-rod, said plunger armature closing said central opening of said partition on a circuit breaking movement of the switch contacts. i

4. A circuit breaker as specified in claim 1, in which the connecting-means between said releasing mechanism and said switchcontacts comprises arms carrying members engageable with and disengageable from the plunger armature to respectively close and openthe switch contacts.

5. A circuit breaker as specified in claim 1, comprising in combination with the magnet-coil, switch contacts on one side of said magnet coil, a releasing mechanism on the other side of said magnet coil and a plunger armature in said magnet coil, 'connectlng means between said switch contacts and said releasing mechanism consisting of two contact-arms pivotally mounted at the sides of said magnet-coil, a separating disk on the lower end of said plunger armature, a roller at the lower end of each of the two-armed contact-arms, said rollers pressing against said separating disk to press together the upper ends of said contact-arms forming the switch contacts, and springs acting on. said contact arms to force the switch contacts apart'as soon as said rollers are released by the attracted plunger armature.

6. A circuit breaker as specified in claim 1 comprising in combination with a casing having a spark space, a magnet coil, switch contacts in said spark space and on one side of said magnet coil, a releasing mechanism on the other side of said magnet coil, means connecting said switch contacts with said releasing mechanisms, and a partition of insulating material between the coil and spark space and forming passages for said connecting means one at each side of said magnet coil.

In testimony whereof I aifix my signature.

VVILHELM LEYHAUSEN. 

